Advice Needed Quattro lnb and diseqc motor.

C

Condar

New Member
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6
My Satellite Setup
80cm Triax with Quattro LNB
My Location
Dublin
Current Setup: Triax 80cm dish with quattro LNB to Skymaster MSP 58 multiswitch locked on to 28.2 E.

Would like to also point to 19.2 E. Have a Technomate DiSEqC H-H TM-2600M3 motor. I can provide power to the motor via one of the quattro LNB feeds. So, feed the Low V output from the LNB to the Motor LNB input and power is supplied to the motor. However, the signals for moving the motor are not passed by the multiswitch. (An alternative is to use two LNBs and no motor. However, aligning the two LNBs correctly (28.2 E and 19.2 E) is not easy as I don't appear to be able to provide the necessary skew angle.) Any ideas how I could get the DiSEqC moving signals to the motor with only the quattro LNB on the dish? A possible suggestion attached?View attachment 123964View attachment 123964
 

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Channel Hopper

Channel Hopper

Suffering fools, so you don't have to.
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A little less analogue, and a lot more crap.
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What receiver are you using ?
 
A

a33

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433
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XSAT410
Clarketech HD4100+
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NL
Hi Condar,
Welcome to the forum!

You need an extra cable to the motor, while not using the motor-to-LNB port of the motor.
(Maybe you need a terminator resistor (with DC-block!) on the motor-to-LNB port; that would be the 'neat' solution. But maybe it works just the same without one.)

So the setup would be like this:

STB -- splitter -- port 1 to multiswitch and quattro LNB (non-motor part of the setup)
----------------------port 2 of splitter directly to diseqc/USALS motor -- and maybe terminator (motor part of the setup)

I guess you know that only one receiver at a time can have the motor control?


If you want to split off the 22kHz motor commands and combine them later on again (as in your picture), mmmm, I guess that wouldn't be easy, and easily be causing problems. But I must confess I never tried it that way.


Greetz,
A33
 
C

Condar

New Member
Messages
6
My Satellite Setup
80cm Triax with Quattro LNB
My Location
Dublin
Hi a33. Thanks for the welcome!

Hi Channel Hopper. The multiswitch has 8 outputs. One of the receivers (for use primarily with 19.2 E) is a Megasat HD 601 V2. That is the receiver I would use to move the DiSEqC motor. The other outputs are connected to other Freesat and non-Freesat STBs. I understand that on those occasions when I would have the dish aimed at 19.2 E, I would not simultaneously have any other satellite (particularly 28.2 E) available. However, 90% of the time the dish will be aimed at 28.2 E.

a33: Is your setup as in sketch #2 attached? A disadvantage of that is the need, as you correctly state, for an additional coax cable. Because the DiSEqC motor would not be connected to an LNB, are you suggesting a terminator to replace the absent LNB? If so, do you have a terminator suggestion? Would the motor be damaged if a terminator was absent?

As I would see it , the default position for the dish would be to 28.2 E. When I wanted to move it to 19.2 E, I would use the Megasat. When finished, I would redirect the dish back to 28.2 E.
 

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A

a33

Member
Messages
433
My Satellite Setup
XSAT410
Clarketech HD4100+
My Location
NL
a33: Is your setup as in sketch #2 attached?
Yes, that is right.
The terminator resistance choice is not critical, as long as it is DC-blocked.

Without a terminator, the motor will not be damaged. Without it an impedance mismatch occurs, which can cause problems in the 22kHz signal transfer and the RF signal transfer, which could cause rather unpredictable malfunctions in reception and motor control.
However, the motor circuit will also have 'some' terminating impedance (as opposed to totally 'open' or 'closed' termination at the end, these are the worst!), so it might be that that would be enough in practice/ in your case. But if you must order some satellite material, a terminating resistor isn't expensive, and the 'neat' solution.

The choice of a splitter is more critical: it must have no diodes! (As the diodes in splitters are usually in the wrong direction for this setup; they are meant for another purpose.) So it must be power pass, both ports, both directions.
A real splitter is much much better that a simple "T-piece"; also for impedance matching reasons.


BTW For a fixed two LNB solution: there are constructions available where you can put a 'side-mast' to your existing mast, which you can set at the needed dish skew angle. If you are watching 19e only with one receiver, only a 'single LNB' with one cable is needed, plus a diseqc switch.
A motor, however, will give you even more choice of satellites.
Just to give you the options.....

Greetz,
A33
 
C

Condar

New Member
Messages
6
My Satellite Setup
80cm Triax with Quattro LNB
My Location
Dublin
Thanks A33 for you very informative and detailed advice. I'll experiment over Easter weekend (more time) and let you know what results.
 
A

a33

Member
Messages
433
My Satellite Setup
XSAT410
Clarketech HD4100+
My Location
NL
Gladly done. Somehow we hobbyists like to help eachother. :)

Keep us posted!

BTW. If you might still be opting for the two fixed LNBs solution: What exactly is the cause for the skewing problem? Maybe we can think of (more) solutions there.
(Rail/Dish skew for dublin would be around 20 degrees, I think?)

greetz,
A33
 
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C

Condar

New Member
Messages
6
My Satellite Setup
80cm Triax with Quattro LNB
My Location
Dublin
Bear in mind that I’m new to this black art of satellite alignment! I did manage to successfully set up the dish with the quattro LNB aimed at 28.2e. I then tried using a 2-way multi LNB holder having the quattro LNB and a regular LNB.

On Dishpointer, and for my location, the requirements are: (there are no values for only 19.2e and 28.2e):

A:

Satellite
: 28.2E, 19.2E(c), 5W
Elevation: 24.8°
Azimuth (true): 149.4°
Azimuth (magn.): 152.4°

Dish Skew: 73.2°

B:

Satellite
: 28.2E ASTRA 2E | ASTRA 2F | ASTRA 2G
Elevation: 21.5°
Azimuth (true): 139.6°
Azimuth (magn.): 142.5°

LNB Skew: -15.3°

C:

Satellite
: 19.2E ASTRA 1KR | ASTRA 1L | ASTRA 1M | ASTRA 1N
Elevation: 24.8°
Azimuth (true): 149.4°
Azimuth (magn.): 152.4°

LNB Skew: -10.2°



I tried A above and could get 28.2e but not 19.2e. Perhaps I didn’t experiment enough. The Dish skew of 73.2° is perhaps the problem as I don’t know how to achieve that value. So a few questions:

1 should the quattro LNB be mounted on the holder so that it’s centrally located; align the dish to 28.2e (e.g Channel 4); and then slide the single LNB on the holder until I receive, for example, Das Erste, on 11836 H?; or

2 should the single LNB be mounted on the holder so that it’s centrally located; align the dish to 19.2e (e.g Das Erste); and then slide the quattro LNB on the holder until I receive, for example, Channel 4?; or

3 somehow, point the dish at 23.7° (which is halfway between 19.2 and 28.2) and then slide each of the LNBs on the holder on either side of the centre until the desired signals are received?

And how to achieve the dish skew of 73.2°? Is dish skew the same as LNB skew? If so, why does Lyngsat refer to LNB skew (when there is only one LN:cool: and Dish skew (when there is more than one LNB?).
 
jeallen01

jeallen01

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Somewhere in England (possibly?)!
I would strongly query any skew value greater than about 30 degrees - values around 8-15 degrees are about right for the UK and Eire (depending of course on where the dish is located). Therefore I suggest you recheck the input values for the calculation that gave 73.2 degrees.
 
jeallen01

jeallen01

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Somewhere in England (possibly?)!
I think you may have incorrectly input your location parameters into dish pointer - using dishpointer.eu and your location as Dublin, 5W is almost directly South of you, and thus, for that Sat, the Mag & Compass settings are around the 180 Deg mark, and not the 150 Deg mark!

Then again, and thinking about this from a wider perspective, I suspect that you may completely misunderstand how to set up a DiSEqC motor and dish with one LNB (be it a single LNB or a Quatro) as that is almost entirely different to setting up a fixed dish with multiple LNBs where you have to set the skew separately on each LNB! On a steerable dish, the skew of the LNB relative to the dish, is pretty much 0 Deg!

I thhink that you need to "go completely back to basics" on the settings for the DiSEqC motor and the dish - Set the motor to 0 Deg Longitude and the dish to around 29 Deg elevation, with 0 deg skew of the LNB in the holder, and gently swing the dish very slightly E & W, and Up & Down, until you get a signal lock on a 5W transponder, which is near-enough your Due South Sat (as 1W is for us in the London area), and then peak that up. Then you gradually expand the arc by driving the motor E and W to the nearest strong sats in each direction and adjust the dish elevation and declination until you get decent tracking across as wide an arc as you want or are able to achieve (5W to 28E should be pretty easy!).

There is a lot of guidance on setting up DiSEqC motors and dishes in this part of the forum, and I think you need to take a good long look at some of those guides.
 
A

a33

Member
Messages
433
My Satellite Setup
XSAT410
Clarketech HD4100+
My Location
NL
Dish skew 73.2? For what satellites combination, at dublin??
When I enter 28e till 5w, I get 100.2 from dishpointer

But to answer: I guess dishpointer takes 90 degrees as 0 degrees (no dish skew). So a skew 100 would in fact be 10 degrees against the horizontal.

Problem with dishpointer and multisatellite skew is however, that some of the Astra calculations take into account the LNB preskew of 7,5 degrees also for the dish skew, which is totally wrong.
I found that out long ago, but don't remember which multisatellite combinations give OK outputs, and which don't. (Mailing dishpointer doesn't help.)
Apart from that: you must choose a combination with the two most outward satellites in your setup, in your case 19e till 28e.
(Added: In that case, dishpointer gives skew 102.8, that is 12.8 against horizontal. Add 7,5 and you get about my 20. :) )

So I use my own approximate calculator for that now.
The about 20 degrees against the horizontal that I mentioned above for dublin for 19,2e and 28,35e come from my calculations.
So when you look into the dish, the 28e LNB would be central (I would firstly choose your option 1), and the 19e LNB would be at the right, and lower.
If you skew the total dish, or just the multifeed rail, is not really important (though skewing the dish would be best).

I hope the dish is big enough, to receive 19e with a 'byrider LNB'?
The LNB-skew (against the horizontal) of dishpointer for the Astras you can trust.

Greetz,
A33
 
C

Condar

New Member
Messages
6
My Satellite Setup
80cm Triax with Quattro LNB
My Location
Dublin
Thanks Guys; you have been really helpful.

For the record, see attachment Dishpointer 3 for a comparison between Dishpointer.com and Dishpointer.eu values. The Skew values for dishpointer.eu are from the front of the dish; dishpointer.com seems to be silent as to which direction you are looking at the dish.
 

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a33

Member
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433
My Satellite Setup
XSAT410
Clarketech HD4100+
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NL
Didn't realize there was a dishpointer.eu. The dishpointer.com is the 'normal' one that I use.

... dishpointer.com seems to be silent as to which direction you are looking at the dish.
There was an explanation at the [?] sign. After a graphic "upgrade", some year(s?) ago, it was lost.

greetz,
A33
 
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